I asked this question yesterday with no definitive answer. Will I notice a marked difference in vegetative growth between a 5000k CFL and a 6500k CFL of the same wattage? I've found a great deal on 55w bulbs but they're not available in a 6500k rating through this particular distributor. I've done everything I can to research an answer but I can't seem to find suggestive evidence that "bluer" is better or if 5000k is sufficient. If the difference in the color temp between 5000k and 6500k is negligible, then I'm going to purchase these bulbs. If I will truly see an increase in vegetative growth with a 6500k lamp, then I'll spend the extra money. Any input would be greatly appreciated. Heiro
Everything I've ever heard says 6500k is the right spectrum. For veg I use MH at that spectrum and it works well. I don't have experience with 5000k so I can't tell you it's wrong, but it doesn't match the conventional wisdom and doesn't match what the bulb makers sell for horticulture. That tells me something. If you have the space and ability to do a side-by-side comparison, go for it and educate all of us. Otherwise I would advise to stick with the tried-and-true.